1. Field of the Invention
The present invention relates generally to a communication system, and more particularly to a method and system for controlling a data rate in a communication system.
2. Description of the Related Art
A process for maximizing throughput supportable in a communication system is an important factor in determining the performance of the communication system. Thus, active research is being conducted on various schemes to maximize the throughput with certain level of reliability in the communication system.
For example, a Single-Input Single-Output (SISO) communication system controls a data rate on the basis of a Signal to Interference and Noise Ratio (SINR) in order to maximize the throughput. Among schemes for controlling the data rate on the basis of the SINR, a typical scheme is Adaptive Modulation and Coding (AMC). The AMC scheme sets a Modulation and Coding Scheme (MCS) level to be used in a signal receiver, for example, a Mobile Station (MS), on the basis of the SINR and controls a data rate on the basis of the set MCS level. That is, when the AMC scheme is used, the data rate of the MS is set only by the SINR therein.
The communication system is developing into a system for providing MSs with services for high-speed large-capacity signal transmission and reception. As the high-speed large-capacity signal transmission and reception are required, a Multiple-Input Multiple-Output (MIMO) communication system is being actively considered which can transmit and receive high-speed large-capacity signals by throughput enhancement, while obtaining space, time and frequency diversity which enables more reliable data transmission.
Because the MIMO communication system uses multiple transmit and receive antennas, its throughput may be degraded when a data rate of the MS is controlled by considering only the SINR of the MS as in the SISO communication system. This is because only the SISO-based SINR is considered without using advantages of the MIMO system which can support either improved throughput and reliability, or both.
Consequently, the scheme for controlling the data rate based on SISO SINR is not proper for the MIMO communication system. Hence, a need exists for a data rate control scheme capable of maximizing throughput in a MIMO communication system.